Simple Fully Automatic Testing Method of Seepage Indices for Low-Permeability Materials

Xizhong Shen,Ling Li,Yingjun Wang

doi:10.3390/w13040477

Abstract

In anti-seepage engineering, quality control and engineering applications are based on the accurate measurement of seepage indices for low-permeability materials. The test used to determine the seepage indices for low-permeability materials adopts an external source to produce water pressure, and the seepage flux produced during the process requires manual measurement; thus, the apparatus used is complex and difficult to operate, thereby lowering the testing efficiency and restricting its application. In this study, a built-in servo motor was used to produce high water pressure with a pressure transmitter, and it controlled and measured the seepage pressure. According to the rotation number of the electric cylinder motor, the volume change of water in the hydraulic cylinder was calculated and, thus, the seepage flux was deduced. A simple fully automatic seepage apparatus for low-permeability materials was designed with a human–computer interface. The results showed the successful calculation of seepage flux as a function of the rotation number of the servo motor through automatic measurement. Furthermore, the replacement of the external high-pressure source with the built-in servo motor enhanced the safety performance, and the human–computer interface enabled an interactive operation and simplified the measurement structure. This simple testing method can provide technical support for quality inspection and construction control of anti-seepage engineering.

Highlights

With the development of society, anti-seepage projects are increasing, such as cutoff walls, continuous walls, and cutoff bodies in underground spaces [1,2]
The testing of low-permeability engineering materials requires a high seepage pressure applied to the specimen, as well as an accurate measurement of small seepage flux; the measurement methods and devices used for high-permeability engineering materials are no longer applicable
Leveraging the properties of the servo motor, motor, we we developed developed aa simple simple fully fully automatic automatic seepage apparatus to test seepage indices for low-permeability materials

Summary

Introduction

With the development of society, anti-seepage projects are increasing, such as cutoff walls, continuous walls, and cutoff bodies in underground spaces [1,2]. Seepage indices mainly include the seepage coefficient and seepage gradient, which are important indices reflecting the permeability of materials. Engineering materials with a seepage coefficient less than 10−6 cm/s are defined as low-permeability materials [3], widely used in the anti-seepage applications for civil engineering [4], water resources [5], transportation [6], environmental protection [7], petroleum manufacturing [8], mining [9], and so on. The testing of low-permeability engineering materials requires a high seepage pressure applied to the specimen (about 2 MPa), as well as an accurate measurement of small seepage flux; the measurement methods and devices used for high-permeability engineering materials are no longer applicable. The main challenge in our research is how to eliminate the potential danger of an external high-pressure source and how to automate the measurement of seepage flux with a structured apparatus

Objectives

Methods

Results

Discussion

Conclusion